AO@SW with Vrala: Simulations and Tests

C. Del Vecchio[1], G. Agapito[1], L. Carbonaro[1], F. Marignetti[2], E. De Santis[2], Y. Coia[2]
[1]National Institute for Astrophysics, Arcetri Astrophysical Observatory, Firenze, Italy
[2]University of Cassino and Southern Latium, Cassino, Italy

VRALA is the ideal candidate as an Adaptive Optics actuator at visible wavelengths. Its electric characteristics variations, suitable current commands, and an effective magnetic circuit geometry provide a 2 kHz correction bandwidth and a 25 mm actuator density. The magnetic core allows unprecedented performances with a negligible thermal impact. Pre-shaping the coil currents greatly simplifies the control system. Equipped with an inductance measure circuit, the current generator also provides the control system with an accurate feed-back signal. COMSOL\'s non-linear model allows to define the optimized geometry, to compute the dynamic response to the closed-loop control system, and to calculate the circuit inductance. The tests performed on a preliminary prototype, match the design results in terms of power and force.